Preheat the oven to gas 6, 200°C, fan 180°C. Line a baking sheet with nonstick baking paper.Put the flour, baking powder, xanthum gum, salt and butter into a food processor and blitz until you have a mix that resembles fine breadcrumbs. Add the egg and about 1 tablespoon of cold water and blitz until the mixture comes together in a ball. Keep an eye on the texture – you may need to add a little more water to ensure the mixture doesn’t crumble too easily. Roll into a flat disc, cover with clingfilm and chill for 10 minutes.

Meanwhile, prepare the filling. Heat the oil in a frying pan. Add the butternut squash cubes and fry over a gentle heat for 6 minutes or until softened. Add the onion and fry for another 5 minutes. Add the garlic and chilli flakes, season well, and fry for a further 2-3 minutes or until the squash is tender.

Put the spinach in a colander and pour over boiling water to wilt. Squeeze dry to remove the excess water and roughly chop. Add this to the butternut squash mix. Add the feta and stir to combine. Set aside to cool.Roll out the pastry to the thickness of a pound coin on a lightly floured surface. Cut out 8 x 10cm (4in) circles using a pastry cutter. Put a spoonful of the butternut squash mix onto the right side of each circle, leaving a 1cm (1/2in) border. Brush the edges with egg and fold over to make a half-moon shape. Press the edges together with your fingers before crimping with a fork to seal well. Repeat to make 8 pasties. Using a skewer, make a small hole in the top of each pasty. Chill for 10-15 minutes or until firm.

Arrange the pasties on the baking sheet, brush all over with beaten egg, then bake for 20 minutes. Brush with egg again and bake for another 5-10 minutes or until golden and crisp. Serve hot as a snack.

Freezing and defrosting guidelines

Freeze before baking. Wrap well in clingfilm and tin foil (to prevent freezer burn) and freeze for up to 3 months. Cook from frozen, adding 10 minutes to the cooking time or until the pastry is crisp and golden and the filling is piping hot.